Google Analytics Troubleshooting & Debugging

Overview

This guide helps you diagnose and resolve common Google Analytics tracking issues for both GA4 (Google Analytics 4) and Universal Analytics. Use the debugging tools and techniques below to ensure accurate data collection.

Debug Mode

GA4 Debug Mode

Enable debug mode in GA4 to see real-time event tracking:

// Enable debug mode for GA4
gtag('config', 'G-XXXXXXXXXX', {
  'debug_mode': true
});

View debug events in DebugView:

Go to Admin → DebugView
Generate events on your site
See events appear in real-time

GA4 Chrome Extension

Install Google Analytics Debugger Chrome extension:

Install from Chrome Web Store
Click extension icon to enable
Open browser console
See detailed GA event logs

Universal Analytics Debug

// Check if UA is loaded
if (typeof ga !== 'undefined') {
  console.log('Google Analytics loaded');
  ga(function(tracker) {
    console.log('Tracker name:', tracker.get('name'));
    console.log('Tracking ID:', tracker.get('trackingId'));
  });
} else {
  console.error('Google Analytics not loaded');
}

Common Issues

No Data in Reports (GA4)

Symptoms: Tracking code installed but no data appears in GA4 reports.

Solutions:

Verify Measurement ID:

// Check your GA4 config
gtag('config', 'G-XXXXXXXXXX');

// Verify Measurement ID in Admin → Data Streams

Check data stream settings:
- Go to Admin → Data Streams
- Click your web data stream
- Verify "Enhanced measurement" is enabled
- Check stream URL matches your domain
Use DebugView:

// Enable debug mode
gtag('config', 'G-XXXXXXXXXX', {
  'debug_mode': true
});

// Check DebugView for incoming events
// Admin → DebugView

Verify gtag.js is loaded:

// Check if gtag exists
if (typeof gtag !== 'undefined') {
  console.log('gtag.js loaded successfully');
} else {
  console.error('gtag.js not loaded');
}

// Check script tag exists
const gtagScript = document.querySelector('script[src*="googletagmanager.com/gtag"]');
if (gtagScript) {
  console.log('gtag.js script tag found');
} else {
  console.error('gtag.js script tag missing');
}

Check network requests:
- Open DevTools → Network tab
- Filter by "google-analytics" or "collect"
- Look for requests to google-analytics.com/g/collect
- Status should be 200 or 204

Events Not Tracking (GA4)

Symptoms: Custom events aren't appearing in GA4.

Solutions:

Verify event syntax:

// Correct GA4 event tracking
gtag('event', 'button_click', {
  'event_category': 'engagement',
  'event_label': 'signup_button',
  'value': 1
});

// Check in DebugView within seconds

Check event name restrictions:
- Must start with a letter
- Only letters, numbers, underscores
- Max 40 characters
- Can't use reserved names (e.g., "page_view", "session_start")

// Good event names
gtag('event', 'signup_completed');
gtag('event', 'video_played');

// Bad event names (will fail)
gtag('event', '1st_event');        // Can't start with number
gtag('event', 'sign-up');          // No hyphens allowed
gtag('event', 'very_long_event_name_that_exceeds_40_chars'); // Too long

Verify event parameters:

// Parameters must follow naming rules
gtag('event', 'purchase', {
  'currency': 'USD',        // Valid
  'value': 99.99,           // Valid
  'transaction_id': 'T123', // Valid
  'items': [                // Valid
    {
      'item_id': 'SKU123',
      'item_name': 'Product Name',
      'price': 99.99,
      'quantity': 1
    }
  ]
});

Check timing:
- Events appear in DebugView immediately
- Standard reports: 24-48 hours
- Realtime reports: Within minutes

Universal Analytics Not Working

Symptoms: UA tracking code not collecting data.

Solutions:

Verify tracking code:

// Check if ga object exists
if (typeof ga !== 'undefined') {
  console.log('✓ UA loaded');

  // Get tracker info
  ga(function(tracker) {
    console.log('Tracking ID:', tracker.get('trackingId'));
    console.log('Client ID:', tracker.get('clientId'));
  });
} else {
  console.error('✗ UA not loaded');
}

Check analytics.js is loaded:

<!-- Verify script tag exists -->
<script async src="https://www.google-analytics.com/analytics.js"></script>

Test page view tracking:

// Manual page view
ga('send', 'pageview', {
  'page': '/test-page',
  'title': 'Test Page'
});

Check network requests:
- Filter Network tab by "collect"
- Look for requests to google-analytics.com/collect
- Verify tid parameter matches your UA-XXXXXXXX-X

Google Tag Manager Issues

Symptoms: GTM container loaded but tags not firing.

Solutions:

Enable Preview Mode:
- In GTM, click "Preview"
- Navigate to your site
- GTM debug panel appears
- See which tags fire on each event
Check container loading:

// Verify GTM is loaded
if (typeof google_tag_manager !== 'undefined') {
  console.log('GTM loaded');
  console.log('Container IDs:', Object.keys(google_tag_manager));
} else {
  console.error('GTM not loaded');
}

Verify dataLayer:

// Check dataLayer exists
if (typeof dataLayer !== 'undefined') {
  console.log('dataLayer exists');
  console.log('dataLayer contents:', dataLayer);
} else {
  console.error('dataLayer not defined');
}

// Push test event
dataLayer.push({
  'event': 'test_event',
  'eventCategory': 'test',
  'eventAction': 'debug'
});

Common GTM mistakes:
- dataLayer defined after GTM container
- Tag triggers not configured correctly
- Variables returning undefined
- Tags paused or blocked

Cross-Domain Tracking Issues

Symptoms: Sessions breaking across domains.

Solutions:

GA4 cross-domain setup:

// Configure cross-domain tracking
gtag('config', 'G-XXXXXXXXXX', {
  'linker': {
    'domains': ['domain1.com', 'domain2.com']
  }
});

Universal Analytics cross-domain:

// Configure UA cross-domain
ga('create', 'UA-XXXXXXXX-X', 'auto', {
  'allowLinker': true
});
ga('require', 'linker');
ga('linker:autoLink', ['domain1.com', 'domain2.com']);

Verify linker parameters:
- Check URLs for _gl parameter (GA4)
- Check URLs for _ga parameter (UA)
- Links should include cross-domain parameters
Test cross-domain tracking:

// Check if linker is working
// Click link to other domain
// URL should contain: ?_gl=1*abc123*_ga*...

// In GA, filter by hostname to see both domains in same session

Ecommerce Tracking Not Working

Symptoms: Purchase or transaction data missing.

Solutions:

GA4 ecommerce setup:

// Send purchase event
gtag('event', 'purchase', {
  'transaction_id': 'T12345',
  'value': 99.99,
  'currency': 'USD',
  'tax': 8.00,
  'shipping': 5.00,
  'items': [
    {
      'item_id': 'SKU123',
      'item_name': 'Product Name',
      'price': 86.99,
      'quantity': 1
    }
  ]
});

// Check in DebugView immediately
// Check Monetization reports after 24-48 hours

Verify required parameters:
- transaction_id (must be unique)
- value (total purchase amount)
- currency (3-letter ISO code)
- items array with at least one item
Check for duplicate transactions:

// Prevent duplicate purchases
let purchaseTracked = false;

function trackPurchase(data) {
  if (!purchaseTracked) {
    gtag('event', 'purchase', data);
    purchaseTracked = true;
  }
}

User-ID Not Working

Symptoms: User-ID not being set or reported.

Solutions:

GA4 User-ID setup:

// Set User-ID
gtag('config', 'G-XXXXXXXXXX', {
  'user_id': 'user_12345'
});

// Or set with event
gtag('set', 'user_properties', {
  'user_id': 'user_12345'
});

Verify User-ID is sent:

// Check in DebugView
// Look for user_id parameter in events

// Or check network requests
// Look for &uid= parameter

Enable User-ID reporting:
- Go to Admin → Data Settings → Data Collection
- Enable "User-ID"
- Create User-ID reporting view

Debugging Tools

GA4 DebugView

// Enable for specific users
gtag('config', 'G-XXXXXXXXXX', {
  'debug_mode': true
});

// Or enable based on URL parameter
const urlParams = new URLSearchParams(window.location.search);
if (urlParams.get('debug') === 'true') {
  gtag('config', 'G-XXXXXXXXXX', {
    'debug_mode': true
  });
}

Google Analytics Debugger Extension

Install and use:

Install from Chrome Web Store
Enable extension
Open DevTools console
See detailed GA logs

Tag Assistant Legacy

For Universal Analytics:

Install Tag Assistant extension
Click extension icon
Click "Enable"
Refresh page
See GA tag status

Network Inspector

// Log all GA requests
function logGARequests() {
  const observer = new PerformanceObserver((list) => {
    list.getEntries().forEach((entry) => {
      if (entry.name.includes('google-analytics.com') ||
          entry.name.includes('googletagmanager.com')) {
        console.log('GA Request:', entry.name);
      }
    });
  });

  observer.observe({ entryTypes: ['resource'] });
}

logGARequests();

Browser-Specific Issues

Safari ITP (Intelligent Tracking Prevention)

// GA4 uses first-party cookies, less affected
// But cookie lifetime reduced to 7 days for client-side tracking

// Consider server-side GTM for longer persistence

Ad Blockers

// Detect if GA is blocked
setTimeout(function() {
  if (typeof gtag === 'undefined' || typeof ga === 'undefined') {
    console.warn('Google Analytics blocked by ad blocker');

    // Send to alternative analytics
    if (typeof alternativeAnalytics !== 'undefined') {
      alternativeAnalytics.track('ga_blocked');
    }
  }
}, 2000);

Content Security Policy (CSP)

<!-- Add GA domains to CSP -->
<meta http-equiv="Content-Security-Policy"
      content="script-src 'self' https://www.googletagmanager.com https://www.google-analytics.com;
               img-src 'self' https://www.google-analytics.com;
               connect-src 'self' https://www.google-analytics.com;">

Data Quality Issues

Bot Filtering

// GA4 automatically filters known bots
// Verify bot filtering in Admin → Data Settings → Data Filters

// For additional bot detection
if (navigator.webdriver ||
    /bot|crawler|spider/i.test(navigator.userAgent)) {
  console.log('Bot detected - tracking may be skipped');
}

Referrer Spam

// GA4 has built-in spam filtering
// For UA, create filter in Admin → View → Filters
// Filter Type: Custom → Exclude
// Filter Field: Campaign Source
// Filter Pattern: spam-domain\.com

Data Import Issues

// Verify data import schema matches
// Check Admin → Data Import
// Review import status for errors
// Ensure primary key matches

Getting Help

Check GA Status

Visit Google Analytics Status Dashboard to check for service interruptions.

Diagnostic Report

// Create comprehensive diagnostic report
function gaHealthCheck() {
  console.group('GA Health Check');

  // Check GA4
  if (typeof gtag !== 'undefined') {
    console.log('✓ GA4 gtag.js loaded');
  } else {
    console.error('✗ GA4 gtag.js not loaded');
  }

  // Check UA
  if (typeof ga !== 'undefined') {
    console.log('✓ UA analytics.js loaded');
    ga(function(tracker) {
      console.log('Tracking ID:', tracker.get('trackingId'));
      console.log('Client ID:', tracker.get('clientId'));
    });
  } else {
    console.warn('○ UA not detected (may be GA4 only)');
  }

  // Check GTM
  if (typeof dataLayer !== 'undefined') {
    console.log('✓ GTM dataLayer exists');
    console.log('dataLayer events:', dataLayer.length);
  } else {
    console.warn('○ GTM not detected');
  }

  console.groupEnd();
}

gaHealthCheck();

Google Analytics Help

Google Analytics Help Center:
- support.google.com/analytics
- Comprehensive documentation
- Video tutorials
Google Analytics Community:
- Ask questions
- Search existing solutions
- Connect with experts
Google Support:
- For Analytics 360 customers
- Direct support available
- Priority assistance

Best Practices

Regular Monitoring

// Create monitoring function
function monitorGA() {
  setInterval(function() {
    if (typeof gtag === 'undefined' && typeof ga === 'undefined') {
      console.error('Google Analytics not detected');
      // Alert your monitoring service
    }
  }, 30000); // Check every 30 seconds
}

monitorGA();

Error Tracking

// Log GA errors
window.addEventListener('error', function(e) {
  if (e.message.includes('gtag') ||
      e.message.includes('analytics') ||
      (e.filename && (e.filename.includes('gtag') || e.filename.includes('analytics')))) {
    console.error('GA Error:', e);
    // Send to error tracking service
  }
});

Testing Checklist

Page views tracking correctly
Custom events firing
Ecommerce events sending
User-ID being set (if applicable)
Cross-domain tracking working (if applicable)
All required parameters included
Data appearing in reports within expected timeframe
No console errors related to GA
Network requests successful (200/204 status)